4.3 TBI running real rough.

Sep 09, 2004 3 Replies
M

I have a '93 GMC with 4.3 TBI engine. It has 185K miles on it and has generally been trouble free. A few months ago ( about 5K miles ) I had some hesitation around 2000 rpm and it was down on power.



I replaced:



Plugs & Wires Cap & Rotor EGR valve O2 sensor



I did each of these one at a time and the 02 sensor seemed to make the most difference.



Anyway, the truck has been running well again, UNTIL this morning. On my way to work, I stopped at the bank ATM. It was running fine when I shut it off, but when I started it back up it had a terribly rough idle. It shudders terribly, and is very under powered under accelleration until I hit about 2500 rpm, then it seems to smooth out and run fine.



Any ideas what may have happened?



Michael


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S

EGR is probably stuck open a bit. Pull it off and see if there is a piece of carbon between the pintle and the seat.

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M

I found the problem. Even tho I have only about 5k miles on the the plug wires, I have one grounding out. I opened the hood last night when it was dark and started it up. Back corner of my engine was lit up like a Christmas tree. I thought that I had put "good" wires on, but apparently not.

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T

You'll have to pay AT LEAST $35-40 for a good set of wires. Anything less will be crap.

-T>

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